Project Summary In this MARI application, we propose to develop and pilot test an intervention to improve the science of treatment as prevention (TasP) and pre-exposure prophylaxis (PrEP) uptake as a public health strategy to decrease new HIV infections among Black/African American and Hispanic/Latino MSM. The proposed research uses a 3-phase study design to address our proposed Specific Aims. First, we will use focus groups to gather feedback on our existing interactive Men2MenRI website that was developed for and by predominately White MSM in Rhode Island that includes information on TasP/PrEP, as well as other health and wellness topics to make it more culturally-tailored for Black/African American and Hispanic/Latino MSM. Second, we will use cognitive interviewing techniques to develop and assess the acceptability of Information- Motivation-Behavioral (IMB)/Social Cognitive Theory (SCT)-grounded social media message content designed to motivate and encourage access to our newly developed and culturally-tailored interactive website. Third, we will pilot test a two-arm trial comparing the combination of sending IMB/SCT-guided messages plus the newly developed and culturally-tailored interactive website (active arm) to the website alone (control arm) to examine whether the combination approach will: 1) increase TasP/PreP uptake (primary outcome); 2) increase knowledge of, more favorable attitudes toward, and increase behavioral intentions of TasP and PrEP use among Black/African American and Hispanic Latino MSM (secondary outcome); and 3) decrease sexual-risk behaviors (exploratory outcome). The proposed study is innovative in the use of a combination approach to TasP/PrEP uptake that leverages advances in social media as a platform for motivating behavior change.